Radially Oriented Single-Crystal Primary Nanosheets Enable Ultrahigh Rate and Cycling Properties of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_2 Cathode Material for Lithium-Ion Batteries

摘要

Ni-rich Li[NixCoyMn1-x-y]O-2 (x = 0.8) layered oxides are the most promising cathode materials for lithium-ion batteries due to their high reversible capacity of over 200 mAh g(-1). Unfortunately, the anisotropic properties associated with the alpha-NaFeO2 structured crystal grains result in poor rate capability and insufficient cycle life. To address these issues, a micrometer-sized Ni-rich LiNi0.8Co0.1Mn0.1O2 secondary cathode material consisting of radially aligned single-crystal primary particles is proposed and synthesized. Concomitant with this unique crystallographic texture, all the exposed surfaces are active {010} facets, and 3D Li+ ion diffusion channels penetrate straightforwardly from surface to center, remarkably improving the Li+ diffusion coefficient. Moreover, coordinated charge-discharge volume change upon cycling is achieved by the consistent crystal orientation, significantly alleviating the volume-change-induced intergrain stress. Accordingly, this material delivers superior reversible capacity (203.4 mAh g(-1) at 3.0-4.3 V) and rate capability (152.7 mAh g(-1) at a current density of 1000 mA g(-1)). Further, this structure demonstrates excellent cycling stability without any degradation after 300 cycles. The anisotropic morphology modulation provides a simple, efficient, and scalable way to boost the performance and applicability of Ni-rich layered oxide cathode materials.